Two weeks ago I brewed a brown ale (5.5 gallon) and hit all my numbers dead on (within reason). Mashed for 60 minutes and calculated a mash efficiency at 82% (OG of 1.064). Great. Today I brewed a wheat beer (4.0 gallon), mashed for 90 minutes and got a mash efficiency of 72% (OG of 1.050)! I'm a bit stumped as to why it's such a big difference.
My process was the same between the two: BIAB no sparge, same crush, used an Igloo cooler for mashing (joys of brewing in upstate NY in the winter), same water, same rest temperature, similar additions to make mash pH ~5.4 (per Bru'nWater, don't have a pH meter). Stirred and checked temperature of the mash every 15 minutes. Refractometer seems to be calibrated correctly.
The only difference that I see between the two (other than the mash time) is the volume in the mash tun. With the 5.5 gallon brown ale, that thing was pretty full and dropped maybe 2F. The 4.0 gallon wheat beer filled maybe 3/4 of the way and definitely lost more than 2F over the course of the 90 minutes.
Now, how can it be that the bigger (gravity-wise) beer which mashed at 60 minutes have a better efficiency than a smaller beer which mashed at 90 minutes? Anyone have any idea what went on here? Kinda bummed about it since the last brew went so well...
My process was the same between the two: BIAB no sparge, same crush, used an Igloo cooler for mashing (joys of brewing in upstate NY in the winter), same water, same rest temperature, similar additions to make mash pH ~5.4 (per Bru'nWater, don't have a pH meter). Stirred and checked temperature of the mash every 15 minutes. Refractometer seems to be calibrated correctly.
The only difference that I see between the two (other than the mash time) is the volume in the mash tun. With the 5.5 gallon brown ale, that thing was pretty full and dropped maybe 2F. The 4.0 gallon wheat beer filled maybe 3/4 of the way and definitely lost more than 2F over the course of the 90 minutes.
Now, how can it be that the bigger (gravity-wise) beer which mashed at 60 minutes have a better efficiency than a smaller beer which mashed at 90 minutes? Anyone have any idea what went on here? Kinda bummed about it since the last brew went so well...